Circulator pumps not turning on

Old 10-14-09, 11:20 AM
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Circulator pumps not turning on

I have 2 heating zones with 2 Grundfos 15-42f pumps. When I turn either thermostat up, the boiler kicks on but the heat never gets beyond the circulator pumps.

I just turned the heating system on for the first time in 6 months
(my hot water is electric). It would be a coincidence if both pumps went bad. Any thoughts on what would be my problem?

Also, Grundfos instruction manual says I can Remove the indicator plug in the middle of the nameplate. The nameplate is one solid plastic disk and there doesn't seem to be a plug. I think I have seen some that have a removable center plug. Is there a way to manually turn the pump on these without a center plug?
Old 10-14-09, 12:58 PM
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If you have a voltmeter and know how to use it safely, troubleshoot for an electrical problem. Check to see if you are getting 24VAC control voltage to the individual pump relays when there is a call for heat. And see if you're getting 120VAC to the pumps. You should be able to trace out where the power is being lost.
Old 10-14-09, 01:17 PM
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You can also try rapping them gently with the handle of a screwdriver. (But I'm with Mike -- probably an electrical problem if both are down.)

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